1. django admin export selected data to csv 2. django admin export data to csv without selected item；

django_admin_export_to_csv.py

"""
from django.contrib import admin

@admin.register(models.XXXX)
class XxxxxAdmin(ExportQueryBaseWithoutSelect, admin.ModelAdmin):
    serializer_class = XxxSerializer       #

    ...
"""
from django.contrib import admin
from django.contrib.admin import helpers
from django.http import HttpRequest, FileResponse
from django.utils.timezone import now
from rest_framework.serializers import ModelSerializer
from rest_framework_csv.renderers import CSVStreamingRenderer


class ExportQueryBase:
    """
    export_to_csv
        1. 导出选择的数据;
        2. 不支持无选择对象导出

    serializer_class
        1. 需要在类中设置 serializer_class -> rest_framework.serializers
        2. 如果没有设置, 使用rest_framework ModelSerializer 导出所有字段
            from rest_framework.serializers import ModelSerializer
    """

    _actions = ["export_to_csv"]  # 允许在admin后台不选择 item的情况下继续;
    serializer_class = None

    @staticmethod
    def auto_model_serializer(model):
        class Serializer(ModelSerializer):
            class Meta:
                model = None
                fields = '__all__'

        Serializer.Meta.model = model
        return Serializer

    @staticmethod
    @admin.action(description="Export Selected or All", permissions=('export_xxxx',))
    def export_to_csv(model_admin: admin.ModelAdmin, request: HttpRequest, queryset):
        model = model_admin.model
        serializer_class = getattr(model_admin, 'serializer_class') or ExportQueryBase.auto_model_serializer(model)
        c = serializer_class(queryset, many=True)
        render_buffer = CSVStreamingRenderer().render(c.data, renderer_context={"bom": True, "encoding": "utf-8"})
        response = FileResponse(render_buffer, content_type="text/csv; charset=utf-8")
        response['Content-Disposition'] = f'attachment; filename="{model._meta.db_table}_{now().strftime("%Y-%m-%d_%H_%M_%S")}.csv"'
        return response

    def get_actions(self, request):
        actions = super().get_actions(request)
        if 'export_to_csv' not in actions:
            actions['export_to_csv'] = (ExportQueryBase.export_to_csv, "export_to_csv", ExportQueryBase.export_to_csv.short_description)
        return actions


class ExportQueryBaseWithoutSelect(ExportQueryBase):
    """

    1. 导出当前查询条件的所有数据, 无需选择对象;
    2. 导出选择的数据;
    """

    def get_params_queryset(self, request):
        # 根据当前的query_params 生成 queryset
        return self.get_changelist_instance(request).get_queryset(request)

    def changelist_view(self, request, extra_context=None):
        selected = request.POST.getlist(helpers.ACTION_CHECKBOX_NAME)  # 当前是否有选择对象
        if not selected:
            try:
                action_index = int(request.POST.get("index", 0))
                action = request.POST.getlist("action")[action_index]
                if action in self._actions:
                    actions = self.get_actions(request)
                    # print(actions)
                    action_func = actions[action][0]
                    return action_func(self, request, self.get_params_queryset(request))
            except IndexError as e:
                pass

        return super().changelist_view(request, extra_context)